Those bright blobs again: Study shows Ceres' spots might have come from within

Scientists may have discovered an ideal site for a new salt mining operation, but extracting the abundant resource would require a little travel, as it's located on Ceres, the largest body in the asteroid belt. Turns out the biggest of the dwarf planet's mysterious bright spots is thanks to the highest concentration of carbonate minerals ever found beyond Earth.

NASA's Dawn spacecraft has been orbiting and observing Ceres and its brightest spots in the large Occator crater for over a year, reaching its lowest orbit in December. As Dawn closed in on Ceres, it became increasingly clear that reflective salts were the most likely explanation for the spots. A new study published in the journal Nature and led by the principal investigator of Dawn's visible and infrared mapping spectrometer, Maria Cristina De Sanctis, finds that the salts may have originated from within the dwarf planet itself.

The study finds that the dominant mineral in the spots is sodium carbonate, which is abundant on our planet and even sold widely as washing soda or soda ash. Because the mineral is not likely to have been delivered to the surface by an asteroid impact, it's suggested that Ceres' internal temperatures are warmer than previously thought and some sort of process is causing an upwelling of the material, perhaps helped along by impacts.

Sodium carbonate is found in hydrothermal environments on Earth and the researchers think the salts on Ceres could be remnants of an ocean or smaller bodies of water that made their way to the surface long ago and froze.

"The minerals we have found at the Occator central bright area require alteration by water," De Sanctis said. "Carbonates support the idea that Ceres had interior hydrothermal activity, which pushed these materials to the surface within Occator."

The new results also found ammonia-bearing salts in the crater, which supports earlier theories that Ceres formed in the outer solar system where ammonia is more prevalent. At one point the dwarf planet may have been as far out as the orbit of Neptune, and then slowly drifted toward its present position.